A Pathway-Based Methodology for Setting Quantitative Targets of Urban Heat Adaptation

As urban temperatures rise at an unprecedented pace due to climate change, cities worldwide are experiencing increasing infrastructure damage and heat-related health impacts. In response, many cities are developing heat-specific adaptation plans and broader resilience strategies. While a wide range of heat mitigation and management measures has been proposed, it remains unclear how these measures are translated into concrete planning targets, how much adaptation progress has been achieved to date, and whether cities are following an appropriate adaptation pathway. The lack of a standardized approach for defining and evaluating quantitative heat adaptation targets poses a major barrier to effective urban heat adaptation planning and implementation.

To address this gap, this study proposes a methodology for quantitatively setting urban heat adaptation targets. Using the latest urban structure data, we diagnose the current thermal environment and project future thermal conditions under a sustainability-oriented target pathway (SSP1) and a high-emission reference pathway (SSP5), assuming the urban structure remains unchanged. By comparing the diagnosed current thermal environment with the heat level associated with the SSP1 target pathway, we quantify the heat risk reduction required for the city to reach a sustainable adaptation state.

The proposed framework enables discussion of necessary concrete adaptation measures by linking the quantified adaptation target to required physical and spatial changes in urban form. Through real-world urban application, we demonstrate how this methodology can diagnose a city's current adaptation pathway, define measurable heat adaptation targets, and support iterative updates as urban structure and adaptation interventions evolve.

This approach contributes to effective urban heat adaptation planning by providing a framework for defining and updating quantitative adaptation targets, which can ultimately be linked to more effective evaluation and implementation of urban heat adaptation strategies.

This work was supported by Korea Environment Industry &Technology Institute (KEITI) through "Climate Change R&D Project for New Climate Regime.", funded by Korea Ministry of Climate, Energy and Environment. (MCEE) (RS-2022-KE002102)